Wire network mapping method and apparatus using impulse responses

Abstract

A method and apparatus for mapping a wire network is disclosed. The method includes obtaining a reflectometry test signal of the wire network. An estimated network impulse response is estimated from the reflectometry response. A wire network model is then initialized, and iteratively improved by simulating an impulse response of the wire network model and adjusting the wire network model to reduce differences between the simulated impulse response and estimated network impulse response.

Description

[0001]This application claims the benefit of U.S. application Ser. No. 60 / 648,836 filed on Jan. 31, 2005, entitled “Wire Network Mapping Method and Apparatus Using Impulse Responses,” which is herein incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates generally to the field of electronic testing. More particularly, the present invention relates to devices and methods for mapping signal paths in electronic systems[0004]2. Related Art[0005]Electronic systems are ubiquitous. An essential component of these systems is their internal signal paths, most typically provided by wired interconnects. Failures in the wiring frequently result in failure of the system. For example, aging wiring in buildings, aircraft and transportation systems, consumer products, industrial machinery, etc. is among the most significant potential causes of catastrophic failure and maintenance cost in these structures. High profile airline crashes ...

AI Technical Summary

Benefits of technology

[0011]It has been recognized that it would be advantageous to develop a technique for mapping an unknown or partially unknown network topology.

[0012]One embodiment of the invention is a method for mapping a wire network. A reflectometry response is obtained from the wire network, and an estimated impulse response is estimated from the reflectometry response. A wire network model is initialized and iteratively improved by simulating the impulse response of the wire network model and then adjusting the wire network model to reduce the differences between the hypothesized network topology and estimated impulse response.

Problems solved by technology

Failures in the wiring frequently result in failure of the system.

For example, aging wiring in buildings, aircraft and transportation systems, consumer products, industrial machinery, etc. is among the most significant potential causes of catastrophic failure and maintenance cost in these structures.

Impedance mismatches can be caused by a variety of things, including for example, breaks in the wire, short circuits, branches, and wire gauge changes.

Interpreting the results obtained with a reflectometry instrument for anything other than simple wires typically requires great expertise, as the reflectometry response can be very complex.

Mismatches also affect the signal passing past the mismatch.

For example, a pair of mismatches can result in an infinite, although decaying, train of reflections as a portion of the test signal bounces back and forth.

Testing of networks of wires has proven challenging.

This is because branches in the network add a further level of complexity to the reflectometry response.

Junctions of wires create an impedance mismatch that can be difficult to distinguish from other types of impedance mismatch.

The number of reflections also tends to grow exponentially with the number of branches in the network; hence, complex network topologies produce extremely complex reflectometry responses.

As a result, even if a distance measurement to a fault can be obtained, the result may be ambiguous, since which branch the fault is located on is not provided.

Analyzing networks of unknown topology can therefore be particularly difficult.

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